It is known the electrical motors employing direct current have their armor placed at the rotor while the field is placed in the stator. This field is a constant magnetic field. In order to be able to perform, these motors needs a constant magnetic field, provided by at least one coil or by permanent magnets. The armor needs a mechanical commutator able to angularly modify the magnetic polarity applied to the rotor when it tends to face the fields of the stator, and this mechanical commutator or “comb” is shaped as a cylindrical collector comprising a plurality of conductive commutator segments placed the one adjacent to the other with an intermediary insulation separating each segment from the other. These segments with the intermediary insulations are placed completing the lateral surface of said cylindrical body, which turns on its axis along with the rotor, having as a rule two collector brushes fixed in electrical contact with the above mentioned commutator conductive segments. This arrangement has the problems well known to the persons versed in the art, namely, the electric arches obtained between the brushes and the segments, and the progressive deterioration of said brushes.
These problems could be overcome eliminating the mechanical commutator, replacing same by an electronic device, delivering the same result, but considering that said collector must be placed at the rotor, by using said electronic commutator we would be giving origin to a new series of problems even greater than the ones we are seeking to overcome.
Therefore, the prior art D.C. motors which neither have a collector or said insulated commutator segments, are motors in which the field generated by magnets is placed within the rotor, while the armor is placed at the stator; hence the electronic commutator is placed at a fixed position and it can receive its input without any problem, while in order to obtain a correct commutation, the position of the rotor could be ascertained by means of magnetic or optical sensors.
Such engines have been found to have a very low power output, since otherwise its rotors would be excessively heavy, its performance is low and the reliability, though it improves the one attained by the conventional motors, because it does not have electrical contacts between its mobile parts.